The Efficacy of Different Antibiotic Compounds in Regenerative Treatment of Immature Necrotic Teeth.

Objectives: Endodontic treatment of immature teeth poses a significant challenge, especially in achieving a proper seal using traditional obturation methods. Revascularization presents itself as an alternative approach to this problem, and the application of triple antibiotic paste (TAP) has been suggested as a means to achieve disinfection during the procedure. This study aims to compare the antibacterial properties of three different antibiotic combinations to assess their effectiveness on root canal disinfection. Materials and Methods: Eighty samples were employed to assess the impact of three antibiotic combinations on Enterococcus faecalis, Escherichia coli, Streptococcus mutans, and a combination thereof. The antibiotics included metronidazole, ciprofloxacin, and cefaclor (CCM), the commonly used TAP, and a double antibiotic paste (DAP) composed of metronidazole and ciprofloxacin. Dentin shavings collected using Gates-Glidden drills were placed in microtubes containing a 2ml standard bacterial suspension. Microtube contents were diluted and cultured on BHI agar plates, with colony counts calculated based on dentine shavings' weight in CFU/mg. Kruskal-Wallis and Dunn's post-hoc tests were used for statistical analysis and P<0.05 was considered significant. Results: A significant difference in mean CFU was observed among all bacterial groups (P<0.05). Dunn's post-hoc analysis showed a significant difference only between the control group (methylcellulose) and the other antibiotic groups. There was no significant difference between the other antibiotic groups in two-by-two comparisons. Conclusion: There was no significant difference in the antimicrobial properties of DAP, TAP and CCM. Therefore, DAP and CCM may be used during regenerative treatment.

Evaluation of the Fracture Resistance of Conservative and Ultraconservative Access Cavity Designs with Different Treatment Modalities: An In Vitro Study.

Introduction: The aim of this study was to evaluate the fracture resistance of endodontically treated mandibular molars using traditional and conservative access cavity preparation. Materials and Methods: In this in vitro study, 100 extracted healthy human mandibular molars were selected and divided into 10 groups (n = 10). Healthy teeth in one group were considered the control group. In three groups, traditional access cavity preparation was done (groups A) without two marginal ridges (A1), with one marginal ridge (A2), and with two marginal ridges (A3). In three groups (group B), two separate access cavities with a dentinoenamel roof without two marginal ridges (B1), with one marginal ridge (B2), and with two marginal ridges (B3) were prepared. In three other groups (groups C), two separate access cavities were prepared only with a dentinal roof without two marginal ridges (C1), with one marginal ridge (C2), and with two marginal ridges (C3), on which root canal treatment was performed afterward. Then, these teeth were subjected to force until fracture. The fracture force and fracture mode of each tooth were recorded and compared between groups by ANOVA, Tukey's post hoc, and chi-square tests using SPSS ver. 23 (IBM, Somers, NJ, USA). Results: The control teeth had the highest mean fracture force (2804.5 ± 338.5 N), followed by a conservative access cavity with a dentinoenamel roof and two marginal ridges (2360.4 ± 181.72 N) and a conservative access cavity with a dentinoenamel roof and one marginal ridge (1812.8 ± 263.9 N), respectively. The lowest mean fracture force was found for the conventional access cavity group without two marginal ridges (399.4 ± 95.2 N). Conclusion: In the condition of this study, with two separate access cavities in mandibular molars and maintenance of the marginal ridges, it is possible to provide teeth with higher fracture resistance against occlusal forces.

The effect of silver diamine fluoride on the bond strength of glass ionomer to the enamel of primary teeth.

Background: Dental caries is a disease which is caused by the acidic by-products of the metabolic processes of dental plaque. Silver components are one of the clinical solutions to prevent caries. This study aimed to investigate the effect of silver diamine fluoride (SDF) application on the shear bond strength of glass ionomer to primary teeth enamel. Materials and Methods: In this in vitro study, a total of 48 anterior sound primary teeth were randomly divided into four groups (n = 12). The control group (G1) consisted of healthy primary teeth, and the three experimental groups (G2-G4) were composed of demineralized primary teeth. The second group did not undergo SDF treatment, the third group underwent SDF treatment, and the fourth group underwent SDF treatment plus polishing. Glass ionomer cylinders were bonded to all specimens and subsequently tested by a universal testing machine to measure the glass ionomer shear bond strength. The type of fracture was examined by a stereomicroscope. Data analysis was carried out using the SPSS 22 statistical software. Data were analyzed by one-way analysis of variance and posthoc Tukey tests (α =0.05). Results: The mean shear bond strength of the glass ionomer was significantly higher in the control group than in the other three groups (P < 0.05). The mean shear bond strength of glass ionomer was significantly higher in the SDF-treated group than in the non-SDF treated and SDF-treated and polished groups (P < 0.05). Conclusion: Although the glass ionomer bond strength to sound enamel was higher than other groups by a significant margin, the application of SDF increases the shear bond strength of the glass ionomer to remineralized white spot enamel in primary teeth.

Comparison of antibacterial activity and fluoride release in tooth-colored restorative materials: Resin-modified glass ionomer, zirconomer, giomer, and cention N.

Background: Considering the important role of fluoride in preventing caries by reducing the number and activity of cariogenic bacteria and introducing new fluoride-releasing tooth-colored restorative materials, this study was performed to compare and evaluate fluoride ion release and antibacterial activity of resin-modified GI, zirconomer, giomer (Beautifil), and Cention N. Materials and Methods: In this experimental in vitro study, eighty samples (20 samples in each group) were prepared, 10 samples for fluoride testing and 10 samples for antibacterial activity. To evaluate the release of fluoride (PPM), fluoride ion-selective electrode was used on days 1st, 3rd, 7th, 14th, and 21st; and antibacterial activities against Streptococcus mutans were examined using direct contact test by absorption of light hourly once every 5 h and days 1st, 2nd, and 7th using an ELISA reader with a microplate reader of 800 TS at a wavelength of 630 nm. The results were analyzed using one-way ANOVA, Tamhane post hoc test, and paired t-test in SPSS software (IBM, Somers, NJ, USA) at a significant level of (P < 0.05). Results: The release of fluoride from materials showed a statistically significant difference (P < 0.001). The maximum mean of fluoride released during the 1st, 3rd and 7th days belonged to the zirconomer group and the minimum for the giomer group. During the measurement period of light absorption from 0 to 24 h after planting, light absorption of foursubstances together was found to be statistically significant (P <.001). Zirconomer light absorption increased on the 7th day, unlike other substances, but still, the minimum light absorption was related to zirconomer. Conclusion: The highest fluoride release was in zirconomer, Cention N, fuji II LC, and giomer, sequentially. Zirconomer showed maximum and giomer showed minimum antibacterial activities.

Evaluation of microleakage in Class II composite restorations: Bonded-base and bulk-fill techniques.

BACKGROUND: This study compared microleakage of Class II cavities restored using bonded-base and bulk-fill techniques with different bases. MATERIALS AND METHODS: In this in vitro study, in 60 extracted human molars, standardized (4 mm × 2 mm × 8 mm) Class II cavities were prepared, such that the gingival floor was located 1 mm below the CEJ. The teeth were randomly divided into five groups and filled with: (1) Fuji II LC + x-tra fil, (2) Ionoseal + x-tra fil, (3) x-tra base + x-tra fil, (4) Grandio Flow + x-tra fil, and (5) x-tra fil only [control group]; in open-sandwich technique, the base thickness was 1 mm. The bases were coated all gingival floor. Except for the first group, where dentin conditioner was used, the Clearfil SE bond was applied before application of the bases and restorative materials as a bonding agent. After 500 thermocycles between 5°C and 55°C, the specimens were immersed in 0.5% basic fuchsine solution for 24 h. The restored teeth were sectioned, and the dye penetration in gingival floor was observed by a stereomicroscope at ×32. The data were analyzed using Kruskal-Wallis and Mann-Whitney tests in SPSS software. The significance was determined at 0.05 confidence interval. RESULTS: The statistical analysis revealed a significant difference in microleakage among the study groups (P < 0.001). The Ionoseal group followed by the control group (x-tra fil composite) had the greatest microleakage. Except for the Ionoseal group, all other groups had significantly less microleakage than the control group. CONCLUSION: The use of bonded-base techniques could reduce microleakage, including those in bulk-fill composite restorations.

Programmed cell death 1 as prognostic marker and therapeutic target in upper gastrointestinal cancers.

Gastrointestinal (GIs) cancers are among the most common causes of cancer related death, and hence the importance for the identification of novel prognostic/predictive biomarkers for detection of patients at an early stage, and for using these to identify novel targeted therapies to improve the efficacy of existing chemotherapeutic regimens. Programmed cell death 1 has been reported as a potential target in several malignancies, and targeting agents are being developed, some already approved by FDA, such as: pembrolizumab, Atezolizumab, Nivolumab. Pembrolizumab that have been approved for the treatment of metastatic non-small cell lung cancer. Here we provide an overview of the mechanism of action PD-1/PD-L1, prognostic value and current progress in clinical trials using PD-1/PD-L1 inhibitors, and the resistant mechanisms at underlie the inhibitory effect of these agents in the treatment of gastrointestinal cancers.

The therapeutic potential of renin-angiotensin system inhibitors in the treatment of pancreatic cancer.

Pancreatic cancer is among the most lethal malignancies with poor prognosis and patients become chemoresistant to current therapies, supporting further investigations to identify new therapeutic regimens in the treatment of this condition. Preclinical and clinical studies now appear to support the role of the renin-angiotensin system (RAS) in the regulation of tumor growth, angiogenesis, and metastasis in different malignancies including pancreatic cancer. These studies suggest that RAS blockers; Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs); could have anti-carcinogenic effects and improve clinical outcomes in the management of pancreatic cancer. Here we provided an overview of ACE inhibitors and ARBs as a potential therapeutic option in the treatment of pancreatic cancer.

Effect of play therapy on behavioral problems of maladjusted preschool children.

OBJECTIVE: The present research was conducted to study the effect of play therapy on reducing behavioral problems of children with oppositional defiant disorder. METHOD: Using multistage cluster sampling, regions 6, 7, and 8 in Tehran were selected. Among kindergartens of these areas, 3 kindergartens which were supported by the welfare organization were randomly selected. Of all the pre-school children of these 3 kindergartens, 40 children who could have behavioral disorder, according to their teachers and parents, were carefully tested. Of them, 16 children who showed severe symptoms of oppositional defiant disorder, were selected via the results obtained from the child symptom inventory questionnaire (CSI-4), teacher's form, and a researcher-made self-control checklist, Then, the subjects were randomly divided into one control and one experimental group. This research is quasi-experimental, and is conducted using pre-test, post-test, and control group. RESULTS: Values of the calculated F for oppositional defiant disorder in control group and experimental group was meaningful after fixing the effect of pre-test (P<0/001). Therefore, a meaningful difference existed between the means of post-test scores of disobedience disorder in the experimental and control groups through the fixed effect of the pre-test effect. Comparison of adjusted means of the 2 groups showed that the mean of attention-deficit hyperactivity disorder (ADHD) in experimental group was lower than control group. Therefore, applying play therapy reduced severity of ADHD in those children in experimental group compared to those in control group who did not receive such instructions. CONCLUSION: Results of this research demonstrates that children's disobedience can be reduced by play therapy.